1. Technical Field
Embodiments discussed herein generally relate to signal transmission devices. More particularly, certain embodiments include, but are not limited to, an antenna array configured to provide a signal phase difference.
2. Background Art
Various directional antenna systems, including flat panel antennae with limited apertures, exhibit a response outside a main beam, known as side lobes. During radio frequency (RF) reception, side lobes can cause unintended reception of adjacent satellite signals. During RF transmission, side lobes can cause unintended interference with other RF signals on adjacent satellites. The Federal Communications Commission (FCC) regulates the levels of these side lobes.
A width of the main beam and the size of side lobes are indicative of antenna performance characteristics. More particularly, a relatively narrow main beam and small side lobes correspond to better directional transmission characteristics. In the case of radio communications, good directional transmission enables more selective communication with a target device and/or better distinguishing by the target device of one transmitter from another nearby transmitter.
In a typical example of a conventional flat panel traveling-wave antenna array, multiple identical waveguides (channels), arranged in parallel with each other, variously transmit respective signals. Radiating elements of these waveguides generate identical sets of side lobes. As a result, the side lobes constructively interfere with one another (sum together), producing significant side lobe levels.
As the number and variety of devices in different environments continue to grow, the amount of wireless communication traffic in such environments will only increase over time. Accordingly, there is expected to be greater value placed on incremental improvements in the suppression of side lobe signal components for directional antenna transmissions.